I'm afraid Mozilla can't promise anything at this point:
>After discussing this with several content blocking extension developers, we have decided to implement DNR and continue maintaining support for blocking webRequest
Then they say blockingWebRequest will be eventually deprecated:
>We’d like to note that it’s still very early to be talking about migrating extensions to Manifest v3. We have not yet set a deprecation date for Manifest v2 but expect it to be supported for at least one year after Manifest v3 becomes stable in the release channel.
> After discussing this with several content blocking extension developers, we have decided to implement DNR and continue maintaining support for blocking webRequest.
They're adopting v3 but not removing this critical use-case.
>After discussing this with several content blocking extension developers, we have decided to implement DNR and continue maintaining support for blocking webRequest
Then they say blockingWebRequest will be eventually deprecated:
>We’d like to note that it’s still very early to be talking about migrating extensions to Manifest v3. We have not yet set a deprecation date for Manifest v2 but expect it to be supported for at least one year after Manifest v3 becomes stable in the release channel.
https://blog.mozilla.org/addons/2021/05/27/manifest-v3-updat...